If mobile network coverage is lost for an extended period of time live services will not be available. Providing CoPilot can still obtain a GPS fix, will continue to navigate the planned route.
In instances when GPS signal is also lost, in situations such as passing through a tunnel, CoPilot will extrapolate the route until a GPS fix is returned. For further details on Tunnel Mode please see the Tunnel Mode article.
The map data is held locally on the device and as a result there is not a risk of the next steps of your journey requiring mobile network connection.